Formulations comprising lipid-regulating agents

ABSTRACT

The present invention is directed to a formulation comprising a lipid-regulating agent dissolved in at least one medium chain glycerol ester of a fatty acid as the primary solvent medium for said agent. One or more emulsifiers may be added to the formulation.

FIELD OF THE INVENTION

The present invention relates to novel formulations for oral administration comprising lipid-regulating agents.

BACKGROUND OF THE INVENTION

2-[4-(4-chlorobenzoyl)phenoxy]-2-methyl-propanoic acid, 1-methylethylester, also known as fenofibrate, is representative of a broad class of compounds having pharmaceutical utility as lipid regulating agents. More specifically, this compound is part of a lipid-regulating agent class of compounds commonly known as fibrates, and is disclosed in U.S. Pat. No. 4,058,552.

Fenofibrate has been prepared in several different formulations, c.f., U.S. Pat. Nos. 4,800,079 and 4,895,726. U.S. Pat. No. 4,895,726 discloses a co-micronized formulation of fenofibrate and a solid surfactant.

U.S. Pat. No. 4,961,890 discloses a process for preparing a controlled release formulation containing fenofibrate in an intermediate layer in the form of crystalline microparticles included within pores of an inert matrix. The formulation is prepared by a process involving the sequential steps of dampening said inert core with a solution based on said binder, then projecting said fenofibrate microparticles in a single layer onto said dampened core, and thereafter drying, before said solution based on said binder dissolves said fenofibrate microparticles, and repeating said three steps in sequence until said intermediate layer is formed.

European Patent Application No. EP0793958A2 discloses a process for producing a fenofibrate solid dosage form utilizing fenofibrate, a surface active agent and polyvinyl pyrrolidone in which the fenofibrate particles are mixed with a polyvinyl pyrrolidone solution. The thus obtained mixture is granulated with an aqueous solution of one or more surface active agents, and the granulate thus produced is dried.

PCT Publication No. WO 82/01649 discloses a fenofibrate formulation having granules that are comprised of a neutral core that is a mixture of saccharose and starch. The neutral core is covered with a first layer of fenofibrate, admixed with an excipient and with a second microporous outer layer of an edible polymer.

U.S. Pat. No. 5,645,856 describes the use of a carrier for hydrophobic drugs, including fenofibrate, and pharmaceutical compositions based thereon. The carrier comprises a digestible oil and a pharmaceutically-acceptable surfactant component for dispersing the oil in vivo upon administration of the carrier, which comprises a hydrophilic surfactant, said surfactant component being such as not to substantially inhibit the in vivo lipolysis of the digestible oil.

Gemfibrozil is another member of the fibrate class of lipid-regulating agents. U.S. Pat. No. 4,927,639 discloses a disintegratable formulation of gemfibrozil providing both immediate and sustained release, comprising a tablet compressed from a mixture of a first and second granulation, and a disintegration excipient operable to effect partial or complete disintegration in the stomach. The first granulation comprises finely divided particles of pure gemfibrozil granulated with at least one cellulose derivative, and the second granulation comprises finely divided particles of pure gemfibrozil granulated with a pharmaceutically-acceptable water soluble or insoluble polymer which are then uniformly coated with a pharmaceutically-acceptable (meth)acylate copolymer prior to admixture with the first granulation. The first and second granulations are present in the final composition in a ratio of from about 10:1 to about 1:10.

U.S. Pat. No. 4,925,676 discloses a disintegratable gemfibrozil tablet providing both immediate and enteric release, which is compressed from a mixture of a first granulation of gemfibrozil with at least one acid-disintegratable binder, and a second granulation formed from the first granulation, but regranulated or coated with an alkali-disintegratable formulation of at least one substantially alkali-soluble and substantially acid-insoluble polymer.

Another class of lipid-regulating agents are commonly known as statins, of which pravastatin and atorvastatin are members. U.S. Pat. Nos. 5,030,447 and 5,180,589 describe stable pharmaceutical compositions, which when dispersed in water have a pH of at least 9, and include a medicament which is sensitive to a low pH environment, such as pravastatin, one or more fillers such as lactose and/or microcrystalline cellulose, one or more binders, such as microcrystalline cellulose (dry binder) or polyvinylpyrrolidone (wet binder), one or more disintegrating agents such as croscarmellose sodium, one or more lubricants such as magnesium stearate and one or more basifying agents such as magnesium oxide.

It is an object of the present invention to provide formulations for oral administration comprising lipid-regulating agents having enhanced bioavailability when compared to commercially available formulations.

SUMMARY OF THE INVENTION

The present invention is directed to formulations for oral administration comprising a lipid-regulating agent, and further at least one medium chain glycerol ester of a fatty acid, such as for example at least one triglyceride, or preferably at least one caprylic/capric triglyceride, as the primary solvent medium for the lipid-regulating agent. One or more emulsifiers may be added to the formulation.

The formulation may be administered directly, diluted into an appropriate vehicle for administration, encapsulated into soft or hard gelatin shells or capsules for administration, or administered by other means obvious to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the plasma concentration in fasted dogs of the formulation of Example 1 and a reference composition.

FIG. 2 is a graph showing the plasma concentration in fasted dogs of the formulation of Example 2 and a reference composition.

DETAILED DESCRIPTION OF THE INVENTION

The bulk lipid-regulating agent can be prepared by any available method, as for example the compound fenofibrate may be prepared by the procedure disclosed in U.S. Pat. No. 4,058,552 or the procedure disclosed in U.S. Pat. No. 4,739,101, both herein incorporated by reference.

Preferred triglycerides include, but are not limited to, caprylic/capric triglycerides. Examples of various caprylic/capric triglycerides are Captex 300™ and Captex 355™, both available from Abitec, and Miglyol 810™ and Miglyol 812™, both available from Creanova.

Suitable emulsifiers include pharmaceutically-acceptable surfactants such as, for example, TPGS (d-alpha Tocopheryl Polyethylene Glycol 1000 Succinate) phospholipids, polyoxyethylene sorbitan fatty acid derivatives, castor oil or hydrogenated castor oil ethoxylates, polyglycerol esters of fatty acids, fatty acid ethoxylates, alcohol ethoxylates, polyoxyethylene-polyoxypropylene co-polymers and block co-polymers. Preferred emulsifiers include polyglycerol esters of fatty acids. A more preferred emulsifier is Caprol 6G20, a polyglycerol-6 dioleate available from Abitec.

Other optional ingredients which may be included in the compositions of the present invention are those which are conventionally used in oil-based drug delivery systems, e.g. antioxidants such as, for example, tocopherol, ascorbyl palmitate, ascorbic acid, butylated hydroxytoluene, butylated hydroxyanisole, propyl gallate, etc.; pH stabilizers such as, for example, citric acid, tartaric acid, fumaric acid, acetic acid, glycine, arginine, lysine, potassium hydrogen phosphate, etc.; thickeners/suspending agents such as, for example, hydrogenated vegetable oils, beeswax, colloidal silicone dioxide, gums, celluloses, silicates, bentonite, etc.; flavoring agents such as, for example, cherry, lemon, aniseed flavors, etc.; sweeteners such as aspartame, saccharin cyclamates, etc.; and co-solvents such as, for example, ethanol, propylene glycol, dimethyl isosorbide, etc.

The solution comprising the lipid-regulating agent is prepared by dissolving said agent in the medium chain glycerol ester of a fatty acid with adequate mixing at or about room temperature. If an emulsifier is used, it is added to the medium chain glycerol ester of a fatty acid with mixing prior to addition of said agent.

The resulting premix liquid comprising said agent may be dosed directly for oral administration, diluted into an appropriate vehicle for oral administration, filled into soft or hard gelatin capsules for oral administration, or delivered by some other means obvious to those skilled in the art. The said premix liquid can be used to improve the oral bioavailability, and/or increase the solubility of said agent.

The invention will be understood more clearly from the following non-limiting representative examples.

EXAMPLE 1

Captex 300 (Abitec) (8.3 gm) was added to a scintillation vial. Caprol 6G20 (Abitec) (1.0 gm) was added to the vial and mixed until it was uniform. Fenofibrate (Sigma) (0.7 gm) was then added to the vial and mixed until it was completely dissolved. 957 mg. of the premix (containing 67 mg. fenofibrate) was added to each of six soft gelatin capsules using a syringe. The capsules were heat sealed and stored.

EXAMPLE 2

Captex 300 (Abitec) (9.3 gm) was added to a scintillation vial. Fenofibrate (Sigma) (0.7 gm) was added to the Captex 300 and mixed until completely dissolved. 957 mg. of the premix (containing 67 mg. fenofibrate) was added to each of six soft gelatin capsules using a syringe. The capsules were heat sealed and stored.

EXAMPLE 3

Capsules prepared by the process described in Example 1 and 2, and from a commercial fenofibrate composition, Lipanthyl 67M (Groupe Fournier) (reference), were administered to a group of fasted dogs at a dose of 67 mg/dog (one capsule per dog). The plasma concentrations of fenofibric were determined by HPLC. Concentrations were normalized to a 6.7 mg/kg dose in each dog. FIGS. 1 and 2 present the resulting data in graph form.

Note: 67 mg dose administered to n=6 dogs; concentrations normalized to a 6.7 mg/kg dose.

The results, provided as mean ±SD, n=6 were as follows:

Lipanthyl 67M (reference):

Cmax=1.88±0.97 mcg/ml

Tmax=1.6±0.9 hr

t_(1/2)=4.5 hr

AUC (0-24)=11.08±9.42 mcg.hr/ml

F(%)=21.1±11.8

Capsules of Example 1:

Cmax=3.19±1.78 mcg/ml

Tmax=1.7±0.5 hr

t_(1/2)=8.1 hr

AUC (0-24)=16.04±5.44 mcg.hr/ml

F(%)=34.7±14.6

Note: 67 mg dose administered to n=6 dogs; concentrations normalized to a 6.7 mg/kg dose.

The results, provided as mean ±SD, n=6 were as follows:

Lipanthyl 67M (reference):

Cmax=1.88±0.97 mcg/ml

Tmax=1.6±0.9 hr

t_(1/2)=4.5 hr

AUC (0-24)=11.08±9.42 mcg.hr/ml

F(%)=21.1±11.8

Capsules of Example 1:

Cmax=3.19±1.78 mcg/ml

Tmax=1.7±0.5 hr

t_(1/2)=8.1 hr

AUC (0-24)=16.04±5.44 mcg.hr/ml

F(%)=34.7±14.6 

What is claimed is:
 1. A composition consisting of a fibrate dissolved in at least one medium chain glycerol ester of a fatty acid.
 2. A composition of claim 1 wherein the fibrate is fenofibrate.
 3. A composition of claim 1 wherein at least one of the medium chain glycerol esters of a fatty acid is a triglyceride.
 4. A composition of claim 3 wherein the triglyceride is a caprylic/capric triglyceride.
 5. A capsule comprising a composition of claim
 1. 6. A capsule of claim 5 wherein the fibrate is fenofibrate.
 7. A method of treating hyperlipidemia comprising the step of administering a therapeutically-effective amount of a composition of claim 1 to a patient.
 8. A method of treating hyperlipidemia comprising the step of administering a therapeutically-effective amount of a composition of claim 2 to a patient. 